Add context qualifier to db_field_log, support plugins for CA read operations

src/ioc/db/dbEvent.c

@@ -626,13 +626,14 @@ int epicsShareAPI db_post_extra_labor (dbEventCtx ctx)
  *  NOTE: This assumes that the db scan lock is already applied
  *        (as it copies data from the record)
  */
-static db_field_log* db_create_event_log (struct evSubscrip *pevent)
+db_field_log* epicsShareAPI db_create_event_log (struct evSubscrip *pevent)
 {
     db_field_log *pLog = (db_field_log *) freeListCalloc(dbevFieldLogFreeList);
 
     if (pLog) {
         struct dbChannel *chan = pevent->chan;
         struct dbCommon  *prec = dbChannelRecord(chan);
+        pLog->ctx = dbfl_context_event;
         if (pevent->useValque) {
             pLog->type = dbfl_type_val;
             pLog->stat = prec->stat;
@@ -655,6 +656,21 @@ static db_field_log* db_create_event_log (struct evSubscrip *pevent)
     return pLog;
 }
 
+/*
+ *  DB_CREATE_READ_LOG()
+ *
+ */
+db_field_log* epicsShareAPI db_create_read_log (struct dbChannel *chan)
+{
+    db_field_log *pLog = (db_field_log *) freeListCalloc(dbevFieldLogFreeList);
+
+    if (pLog) {
+        pLog->ctx  = dbfl_context_read;
+        pLog->type = dbfl_type_rec;
+    }
+    return pLog;
+}
+
 /*
  *  DB_QUEUE_EVENT_LOG()
  *

src/ioc/db/dbEvent.h

@@ -73,6 +73,8 @@ epicsShareFunc void epicsShareAPI db_post_single_event (dbEventSubscription es);
 epicsShareFunc void epicsShareAPI db_event_enable (dbEventSubscription es);
 epicsShareFunc void epicsShareAPI db_event_disable (dbEventSubscription es);
 
+epicsShareFunc struct db_field_log* epicsShareAPI db_create_event_log (struct evSubscrip *pevent);
+epicsShareFunc struct db_field_log* epicsShareAPI db_create_read_log (struct dbChannel *chan);
 epicsShareFunc void epicsShareAPI db_delete_field_log (struct db_field_log *pfl);
 
 #define DB_EVENT_OK 0

src/ioc/db/db_field_log.h

@@ -56,6 +56,12 @@ typedef enum dbfl_type {
     dbfl_type_ref
 } dbfl_type;
 
+/* Context of db_field_log: event = subscription update, read = read reply */
+typedef enum dbfl_context {
+    dbfl_context_read = 0,
+    dbfl_context_event
+} dbfl_context;
+
 #define dbflTypeStr(t) (t==dbfl_type_val?"val":t==dbfl_type_rec?"rec":"ref")
 
 struct dbfl_val {
@@ -69,7 +75,8 @@ struct dbfl_ref {
 };
 
 typedef struct db_field_log {
-    enum dbfl_type     type;  /* type (union) selector */
+    enum dbfl_type   type:2;  /* type (union) selector */
+    enum dbfl_context ctx:1;  /* context (operation type) */
     epicsTimeStamp     time;  /* Time stamp */
     unsigned short     stat;  /* Alarm Status */
     unsigned short     sevr;  /* Alarm Severity */

src/ioc/rsrv/camessage.c

@@ -508,6 +508,7 @@ static void read_reply ( void *pArg, struct dbChannel *dbch,
     int status;
     int v41;
     int autosize;
+    int local_fl = 0;
     long item_count;
     ca_uint32_t payload_size;
     dbAddr *paddr=&dbch->addr;
@@ -565,8 +566,21 @@ static void read_reply ( void *pArg, struct dbChannel *dbch,
         return;
     }
 
+    /* If filters are involved in a read, create field log and run filters */
+    if (!pfl && (ellCount(&dbch->pre_chain) || ellCount(&dbch->post_chain))) {
+        pfl = db_create_read_log(dbch);
+        if (pfl) {
+            local_fl = 1;
+            pfl = dbChannelRunPreChain(dbch, pfl);
+            pfl = dbChannelRunPostChain(dbch, pfl);
+        }
+    }
+
     status = dbChannel_get_count ( dbch, pevext->msg.m_dataType,
                   pPayload, &item_count, pfl);
+
+    if (local_fl) db_delete_field_log(pfl);
+
     if ( status < 0 ) {
         /*
          * I cant wait to redesign this protocol from scratch!
@@ -647,6 +661,8 @@ static int read_action ( caHdrLargeArray *mp, void *pPayloadIn, struct client *p
     void *pPayload;
     int status;
     int v41;
+    int local_fl = 0;
+    db_field_log *pfl = NULL;
 
     if ( ! pciu ) {
         logBadId ( pClient, mp, 0 );
@@ -689,8 +705,21 @@ static int read_action ( caHdrLargeArray *mp, void *pPayloadIn, struct client *p
         return RSRV_OK;
     }
 
+    /* If filters are involved in a read, create field log and run filters */
+    if (ellCount(&pciu->dbch->pre_chain) || ellCount(&pciu->dbch->post_chain)) {
+        pfl = db_create_read_log(pciu->dbch);
+        if (pfl) {
+            local_fl = 1;
+            pfl = dbChannelRunPreChain(pciu->dbch, pfl);
+            pfl = dbChannelRunPostChain(pciu->dbch, pfl);
+        }
+    }
+
     status = dbChannel_get ( pciu->dbch, mp->m_dataType,
-                  pPayload, mp->m_count, 0 );
+                  pPayload, mp->m_count, pfl );
+
+    if (local_fl) db_delete_field_log(pfl);
+
     if ( status < 0 ) {
         send_err ( mp, ECA_GETFAIL, pClient, RECORD_NAME ( pciu->dbch ) );
         SEND_UNLOCK ( pClient );